Detroit Mayor Dave Bing said the city will put workers on furlough beginning Jan. 1 to avoid running out of cash after the City Council decided not to approve a law contract that was required before the state would release crucial money from bond-sale proceeds.

Bing said the furloughs won’t include police, firefighters, EMS workers or employees of departments that raise revenue, such as tax collections.

But it’s likely thousands of city employees will have to adjust to unpaid time off as Detroit grapples with a sudden cash shortfall of up to $30 million. The shortfall is being blamed on the City Council’s rejection of a contract with the law firm Miller Canfield, which Bing hired to advise him on matters related to Detroit’s fiscal stability agreement with the state.

Bing today lashed out at council members who voted 8-1 Tuesday night at a packed hearing in City Hall not to authorize the $300,000 contract. The council said Miller Canfield has conflicts of interest because it played a key role in drafting the now-dead state emergency manager law and the city’s consent agreement with the state.

“I wish I knew what was going on on the 13th floor,” Bing said at a news conference this afternoon. “I’m interested in one thing, and that is to make sure out city is fiscally stable. That’s my focus now, and I’m not going to get away from that.”

The furloughs are sure to further strain a city workforce that has endured hundreds of layoffs and past furloughs as Detroit struggles to right its finances under an agreement that provides major state oversight of the city’s budgets.

It wasn’t clear how long the furloughs would last, but Bing chief financial officer Jack Martin said the administration was working with the city’s human resources department to determine who would be put on furlough and when.

Martin said the city won’t be in danger of running out of cash once the furloughs are implemented. The city says it could see as much as a $5 million shortfall needed to meet payroll by mid-December — a number that grows to $47 million by June 13, underscoring the depths of the city’s money crisis.

Bing said he wouldn’t let the City Council dictate who he hires as his lawyers. He’s faced a drumbeat of criticism from council members and union leaders, who question the legality and ethics of hiring the private law firm. Council members also have sought documents, including contracts and billings, to show what work Miller Canfield has done for the mayor. The Bing administration says those documents are shielded by attorney-client privilege and are exempt from disclosure under the state’s Open Meetings Act.

Bing said he was “very much frustrated” by the councils’ decision.

“It keeps us from moving forward,” he said. “Every time we lose time, it makes things that much more difficult.”

Bing and a spokesman for state Treasurer Andy Dillon said they believe there is room to negotiate on the city ultimately receiving the $10 million in bond-sale proceeds this month and possibly another $20 million in December – cash critical to the city’s ability to meet payroll and pay bills.

The contract was one of several reform actions the state and the Bing administration had agreed the city must meet to get proceeds from $137 million in bonds the city sold to keep solvent while it undergoes a restructuring of city government under state oversight.

Council members accused Bing of agreeing to terms that held bond money hostage for a single contract for one law firm.

City union leaders said they will seek criminal investigations of the Bing administration’s handling of the deal with the state, in which the city must meet key reform benchmarks to receive portions of the bond money now held in escrow by the state Treasury.